Sameen Rashid M.phil pharmacology

1. Contraceptivesare usedto preventunwanted pregnancy. Hormonal contraceptivesconsistof one
or more syntheticfemale sexhormones(estrogenand progestinor progestinonly).These sex
hormonespreventpregnancy by blocking the normal process of ovulation.They may also alter the
liningof the uterus (endometrium) sothat it is unable to support a fertilizedeggandthey change the
mucus in the cervix so that it is hard for the spermto travel hence conceptionis lesslikelyshould
ovulationoccur.
These hormonesare eithertaken as regular dosesin pill form (oral contraceptives),or are
administeredthroughthe skin by meansof a patch impregnatedwith hormones.They can alsobe
givenby three monthly injectionsofa longacting progestin,or by subcutaneousimplants of
progestin.They are also available as hormonal intrauterine devicesand vaginal rings.
Some of them are:
Levonorgestrel/ethinyl estradiol Aviane
Ethinyl estradiol/ethynodiol Zovia
Ethinyl estradiol/norethindrone Lo LoestrinFe
Levonorgestrel/ethinyl estradiol:
Preventingpregnancy.It may be usedfor other conditionsas determinedbyyour doctor.
Levonorgestrel/ethinyl estradiol isacombination birth control pill and folate supplementkit.The
birth control pill works by preventingovulation,alteringthe cervical mucus,and changing the liningof
the uterus.The folate supplementworks by improvingnutritionstatus.
Ethinyl estradiol
thinyl estradiol is a derivative of17β-estradiol (E2),the major endogenousestrogeninhumans. EE2 is
an orally bioactive estrogenused inmany formulationsof combinedoral contraceptive pillsand is one
of the most commonlyusedmedicationsfor this purpose.
Transdermal ethinyl estradiol carries a greater risk of clot formation and venousthromboembolism
than naturally occurring 17β-estradiol,which some have theorizedto be relatedto differentamounts
of hepaticmetabolismafter absorption. The same contraindications and precautionsapply for EE2 as
with other estrogenmedications.
Estinyl was a preparation of EE2 alone that was used for the management of menopausal symptoms
and female hypogonadism.
EE2 is releasedintothe environmentasa xenoestrogenfromthe urine and fecesof people whotake it
as a medication.
The major concern with unopposedestrogen(withoutprogestogen) isof endometrial cancer.As such,
the medicationisgenerallyprescribedwith progesterone inthe settingof birth control.
Pharmacology of ethinyl estradiol:
While E2 is readilyabsorbed when taken orally,it is also quickly inactivatedby the liver.Substitution
at C17 ofthe estrane steroid with an ethinyl group servedto provide an estrogenthat is much more

2. resistant to degradationand pavedthe way for the developmentoforal contraceptives.
EE2 is absorbedin the small intestine and reachesa serumpeak about 2 hours later. It undergoes
extensive metabolisminthe liverinvolvingthe cytochrome P450 3A4 isoenzyme.EE2 and its
metabolitesare excretedwith the bile.Due to the effectofenterohepaticcirculationa secondpeak is
seenseveral hours later. Individually,wide variationsexistinthe overall absorption process,and can
be furthermodifiedbydrugs (i.e.antibiotics) that affectthe enterohepaticcirculationor liver
enzymes.In circulationEE2 is almost fullybound to plasma albumin.It ismetabolizedby
hydroxylationof the aromatic ring and excretedinboth fecesand urine,in part as glucuronide and
sulfate conjugate.
EE2 is hormonallyeffective byactivating the estrogen receptorand thus is an estrogen.It findsits
most common use in the estrogen-progestincombinationpreparationsoforal contraceptives.Over
time,formulationshave decreasedthe EE2 dose from as high as 100 μg to as low as 10 μg in
LoLoestrin Fe.
Levonorgestrel
Levonorgestrel isa manufacturedhormone usedin a number of birth control methods.In pill form,
sold underthe brand name Plan B among others,it is useful within120 hours as emergencybirth
control. It becomeslesseffective the longerafter sex and only works before pregnancyhas occurred.
It is also combinedwith an estrogento make combinedoral birthcontrol pill.Withinan IUD,sold as
Mirenaamong others,it is effective forlongterm preventionofpregnancy. An implantable form of
levonorgestrel isalsoavailable in some countries.
Common side effectsinclude nausea,breasttenderness,headaches,and increased,decreased,or
irregular menstrual bleeding.Ifusedas a form of emergencycontraceptionduring pregnancy there is
no evidence itaffectsthe baby. It is safe to use during breastfeeding.Birthcontrol that contains
levonorgestrel will notchange the risk of sexuallytransmittedinfections.It works mostly by
decreasingovulationand closing offthe cervixto preventthe passage of sperm.
Levonorgestrel was firstmade in the 1960s and its use as a methodof birth control.
Uses:
Oral birth control
Emergencybirth control
Intrauterine device
Contraceptive implants
Hormone replacementtherapy